


The Fire From My Belly (The Beat From My Heart)

by Kawaiibooker



Series: V one-shot [8]
Category: Metal Gear
Genre: Accidental Plot, Dirty Talk, Established Relationship, First Time, I love that that tag exists because that's exactly what happened, M/M, Plot What Plot/Porn Without Plot, Post-TPP, Prosthesis, Rough Sex, Tbh this is all an elaborate excuse to write Sub!V, Venom Headcanon, sort of
Language: English
Status: Completed
Published: 2016-02-16
Updated: 2016-02-18
Packaged: 2018-05-21 03:18:44
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,589
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6035878
Author URL: https://archiveofourown.org/users/Kawaiibooker/pseuds/Kawaiibooker
Summary: <blockquote class="userstuff">
              <p>Kaz gets some prosthetics (finally). It leads to some important revelations.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> V-series setting, early 1987. As such, Venom Snake (aka Vincente Ruiz or "V") comes from Uruguay.

**Notes for the Chapter:**

> Unbetaed.

“Ready? Go!” _Thump._ “Again!”

Shuffling feet, heavy breathing.

“You don’t have time to hesitate in the field. Ready? Go!” _Thump._ “Better. Again!”

Rounding the corner to the gym, Kazuhira Miller is greeted by the forceful sound of bodies hitting the matted floor. He pauses at the entrance, taking off his wet coat and dirtied shoes as he watches a few dozen fresh recruits pick themselves up from the ground with pained groans. He places his belongings neatly into one of the provided lockers, then makes his way around the back of the room so he isn’t seen by the soldiers. While some do better under the pressure of their commander watching them, most just get clumsy and distracted instead. They redo the exercise, downing their opponents in two quick moves.

Besides, the stakes are already higher than usual considering their instructor today is none other than their new Boss. Venom Snake is pacing in front of them, his single eye observing the execution of his orders sharply before he barks corrections, telling them to repeat the process. If he takes note of his partner’s presence, he doesn’t show it.

 _Thump._ Kaz winces in sympathy, remembering his first CQC lessons back in the day. He’d been sore and bruised for days, but it was his wounded pride that was the worst to bear. _Nothing like being smashed to the ground to make you rethink your position in life..._

At the same time, this experience is where all Diamond Dog's deep-seated devotion for their Boss comes from. Even the wildest and most stubborn turn to putty in his capable hands, accepting him as their superior in the most primal sense before the idea takes root in their hearts, too.

“Good. That’s enough for today. Get some food and a shower, then resume your duties. You got one hour. Dismissed!”

“Yes, Boss!” The recruits salute and start filing out, walking in small groups and talking happily in a dizzying amount of languages.

Snake is rubbing a towel over his sweaty face when Kaz walks up to him, relatively silent except for the small clicking of metal toes on the black mat. “What do you think?” he asks, picking up Venom’s water bottle to offer it to him. Now that he doesn’t need his crutch anymore, he relishes the ease with which he can do small things like this.

“Some are more talented than others, but all in all a good bunch.” Snake replies, thanking him for the water with a grunt. His Adam’s apple bobs with each swallow as he drinks half of its content in one go. He throws the plastic bottle to the ground together with his towel and turns to Kaz, tugging at his sweat-soaked shirt that sticks to his sculpted body. “Eager to please, but that’s no surprise. They volunteered, after all.”

Kaz hums and tries not to stare too much – even if they are alone now, the gym is a public space and that means keeping his hands to himself... outside of professional purposes, of course. It’s fortunate for him that he actually has a good reason to be here.

“Still got some energy left for a few rounds? I want to give these here a try.” He casually waves with his artificial arm. It’s attached to his shoulder and parts of his back with tight straps that wrap around his torso, most of it hidden by the loose black shirt he’s wearing. His leg prosthesis is made from the same tarnished gray metal, fitting snugly around his stump.

Both are custom-made for him by their resident bionic engineer, who looked so relieved to finally get the order to work on them that Snake had to shut him up with a tight smile and a hand on his shoulder, subtly shifting his bulk between them to keep Kaz from doing something regrettable.

It’s... weird after two and a half years of nothing but scars and phantom pain, but Kaz can’t deny it feels good to have his mobility back. Getting rid of that damned crutch had been a real treat, too. The current design of the prosthetics is the result of a few different ones they tried and dismissed over the course of two months, even if the last pair was nearly perfect already.

“Yeah, sure. Need some help warming up?” Venom smiles with that fond glint in his eye and, well, there’s the other reason he finally relented in his long fight against better equipment. Kaz feels his lips tug into a half-smile of his own and he nods, taking a moment to draw up his hair into a loose pony tail to get it out of his face.

He’s ready to go but Snake reaches for his face with a chuckle, pulling off his aviators and setting them aside carefully. “One of these days...” he mumbles, but keeps the rest of it to himself as Kaz interrupts him with a huff.

They start out slow, doing some stretching and then some easier moves to get into the headspace they need for this. Kaz’s ever-working mind slows down, focuses on the simple translation of visual and kinetic stimuli into appropriate reactions. He has to admit that he’s gotten unused to actual combat, letting his CQC slide in favor of less frustrating muscle workout that served its purpose in keeping him fit well enough. Still, he’s pretty sure Venom is going easy on him, and grits his teeth.

They amp the difficulty without outward communication, going through the motions like a practiced dance – until Kaz stumbles on his new limb and Snake uses the opening to trip him further and throw him to the ground. The air rushes out of his lungs; there’s a twinge of pain in his shoulder as the socket of the prosthesis presses into it uncomfortably. “Damn”, he wheezes but answers Venom’s questioning glace with a wide grin. The adrenaline spreads through his veins instantly, the rush of physical exertion a sensation he missed dearly. Kaz picks himself up from the ground and rolls his shoulder to loosen up the aggravated muscles.

“Try to block more with your right to absorb the damage. Same with your leg – trust it to hold up, and use the material to your advantage. Don’t worry, the prosthesis can take it”, Snake instructs, returning to their initial position. Kaz does the same, accepting the advice with a tight nod.

“Ready? Go!” and they’re at it again.

Their surroundings blur as they clash time and time again. Kaz finds himself twisted into a kneeling position or on his back at the end of every one of them – still, it takes longer each round for Venom to find an opening, trying out different angles when Kaz successfully blocks his blows or turns out of his grip fast enough.

It’s one of those times that Kaz notices Snake is avoiding one specific move: The choke hold on his neck. The instinct to use it is there; he can see it in the way his arm twitches to wrap itself around his throat, but Snake hesitates in the last second and twists his arm instead. The result is the same – Kaz falls to his knees with a hiss, staying in that position until he is released a second later.

“You good?” Venom asks softly, concern bleeding through his otherwise guarded persona during training. Kaz nods again, getting to his feet and into position swiftly. He’s determined to catch Snake off guard and that little observation just now gave him an idea how.

They start as they always do, assessing the other carefully before Venom strikes and Kaz blocks, metal clanging against metal. It takes trading a few blows and kicks to get there, but eventually Kaz fakes a misstep, creating an opening for Snake to use – and again, his partner freezes for the blink of an eye. It doesn’t take much – one tight grip and a vicious twist to his flesh arm – and Venom gasps as he’s pushed to the ground and onto his stomach, Kaz’s knee placed squarely on his back.

“Got you”, Kaz says smugly between heaving breaths, relaxing the painful hold but remaining in that position to savor the victory. “What was that about not hesitating? You should follow your own advice, Snake.”

His partner merely shifts under his weight, panting. “ _Mierda._ I hoped you wouldn’t catch up on that...” He turns his head to the left to look over his shoulder at Kaz, rolling his eye at the smirk on his face. “Yeah, yeah. Well done. Can I get up now?”

He hums and removes his knee from his back. Venom grumbles and tries to right himself despite his arm still being twisted behind his back, throwing another glance at his partner. “Kaz?”

“I don’t know, V”, Kaz replies, pensively. The position has him sweating for entirely unprofessional reasons; he checks the room – still empty – before he lets his hand wander idly down Snake’s firm back and just under the hem of his shirt, toying with the sharp jut of his hipbone. “I’m kinda liking it up here.” Still, he starts pulling away–

Venom groans and relaxes into the hold. Kaz’s eyebrows raise at the unexpectedly strong reaction and he experimentally tightens his grip again, leaning forward to rest his groin against his lover’s backside. He’s rewarded with another moan that Snake tries to muffle at his shoulder, shooting him a heated look that’s probably supposed to be a warning – _We’re in public, Kaz_ , he reads in the expression on his face – but mostly shows desire, down to the way his pupil is dilated.

“Te gusta, mmh?” Kaz murmurs, rolling his hips once to drag his clothed cock against him. Venom exhales and shifts, pushing back into the pressure. It isn’t exactly a surprise, but still the first time Kaz is made aware of the fact that his lover might like being submissive. _Huh._

Before he can explore that little revelation, though, he hears steps accompanied by the jingle of spurs. Kaz growls but stays put, glaring at Ocelot as the man enters the room and stops in his tracks, blinking once in obvious surprise before he sighs. “Keep it in your pants, gentlemen. Boss, there’s something I need to show you over at intel, if you have the time?” The tone of his voice suggests he won’t accept a quickie as a valid excuse.

“Sure”, Venom grunts under Kaz, making no move to change the fact that they’re in a very compromising position in the middle of the gym. Kaz huffs and finally releases him, planting a kiss between his shoulder blades before he gets up.

Despite his... _dislike_ for the Russian, Kaz is smug about the way Ocelot can’t quite hide the jealousy. He doesn’t know if it’s really Venom Snake he wants or if it’s the general notion that it’s Big Boss he’s bedding that puts him off, but whatever the reason, it’s there and it almost makes the interruption worth it. Almost.

Kaz straightens his pony tail and picks up his sun glasses, placing them squarely on his nose where they belong. Turning back around, he’s treated to the sight of Venom rearranging his sweatpants to hide the obvious bulge of his half-hard cock. The unamused look he levels on Kaz would scare the shit out of most people but he merely smiles sweetly, patting his shoulder.

“I’ll let you two get to it, then. Don’t forget those time sheets you owe me for this month, Snake.”

He bundles his coat under his arm, slips on his shoes and takes his leave, nodding at Ocelot on his way out.

 

Kaz is very glad he only has to walk a few yards to his own quarters.

**Notes for the Chapter:**

> Spanish translations:
> 
> mierda - shit
> 
> Te gusta? - Do you like it?/You like this, don't you?


	2. Chapter 2

**Notes for the Chapter:**

> Unbetaed.

Kaz sorts through the neat pile of paperwork on his desk, noting with some satisfaction that everyone submitted their expected work load for the month in form of a standardized time table.

It’s one of the measures they’ve taken to ensure every Diamond Dog keeps to their assigned shifts, but also remembers to schedule enough hours of free time and rest in between – including the commanding ranks. Of course, there’s no way to verify if every single duty roster lines up with the time sheets, but it’s more of a self-control device anyways. And it has helped already: Some of the soldiers took it upon themselves to remind their colleagues to take a break once in a while, referring to the dates they had put down earlier that month.

“Aha!” he mumbles to himself as he pulls out one of the forms that’s filed to _Vincente Ruiz, Codename: Venom Snake, Rank: Big Boss_ and starts leafing through it. The lines are filled with only a few fixed appointments – like the CQC lessons every Friday morning, 8 am to 12 am – and a lot of question marks. If they’re honest, the application of time sheets on Snake doesn't make much sense as he can’t really anticipate any of the longer missions he goes to, but he insisted on doing it anyways to set a good example for the soldiers.

Kaz scans through the entries before he catches sight of the one for the current day. Beneath the CQC lessons and a hastily scrawled note he deciphers to mean “Intel Meeting w/ Ocelot”, the rest of the day is dashed out with “R&R” written over it. Kaz barks out a laugh, shaking his head fondly. _That cheeky bastard._

It only takes a few moments to adapt his own time sheet accordingly.

*

The door to his office opens with a loud _bang_. Kaz almost jumps out of his skin, managing to set down the coffee he was about to drink with minimal sloshing; he glares at whoever decided to just barge in–

Strong hands take him by the lapels of his coat and drag him from his desk chair to the adjacent wall. Kaz’s sour mood brightens instantly and he smirks, clinging to the broad shoulders for balance before he grasps the man by his shirt with both hands, ripping it a bit in the process. He's still getting used to the strength of his new limb.

Venom Snake lets himself be pushed against the hard surface. A grin flashes across his face, uncaring for his ruined clothes as he starts unbuttoning Kaz’s shirt, running his hands down the bared skin of his stomach. “You have time, right?” he says, voice rumbling deep in arousal and Kaz feels his groin tighten at that tone. _Seems like I wasn’t the only one distracted today._

“Even if I didn’t, I do now”, he replies equally as husky, lifting his hands to cradle Snake’s face and kiss him, hard. Both groan into the messy mesh of lips and tongue; Kaz marvels at the way his partner surrenders to him almost instantly, leaning into the forceful nipping on his bottom lip eagerly. Kaz breaks the kiss, panting and rolling his stiffening erection against Venom’s firm thigh. He looks into that half-lidded eye, at the high color on his cheeks. “God, V– Why didn’t you say something? If I’d known...”

“I didn’t think you’d like it”, Snake murmurs, out of breath. His blush deepens. “Besides, it would’ve been complicated... You know...” His fingers trace the edge of the dark gray prosthesis where it meets Kaz’s pale shoulder.

Kaz snorts. “That’s an excuse if I ever heard one. We can discuss this later, though.” He kisses him again, lighter this time, and tugs on the sweatpants hanging low on his hips. “Close the door and get rid of these. If we’re doing this, we’re doing it right.”

Venom straightens up at the command, doing as he’s told efficiently. Kaz uses the time to throw off his coat and aviators on the desk, narrowly avoiding the mug and the stack of papers beside it; he loosens his tie to get rid of his opened shirt completely, revealing the complex strap-system that holds his prosthesis.

Then, Venom steps up behind him, pressing the entire length of his naked body against Kaz's back and his face against his neck, breathing him in. Those broad hands snake around his torso to stroke his chest, cold metal leaving a trail of goose-bumps behind. Kaz moans softly when they move lower and cup his bulge through his trousers, arching into the touch  – he almost forgets what they wanted to do, but manages to cling to the memory of his lover spread under him just this morning, sweating and panting.

“Bed”, he gasps, forcing himself to turn out of the tight embrace. The look on Snake’s face is intense, want written all over his face; he eyes the desk and Kaz can see the gears turn in his mind. “Nope, forget it. I didn’t work on those all day just to ruin them. Bed, _now_.”

Venom nods, taking Kaz’s bionic hand with his own red one, tugging him in the right direction once but leaving the lead to him. Kaz tangles their metal fingers together clumsily, burying the others in that pepper and salt hair to free it from the pony tail, pushing him back until his legs hit the edge of the mattress and they tumble down on it together.

It takes a bit of coordination and a few adjustments to their position but soon, they’re lost in each other’s mouths again, Kaz rutting his still-clothed erection almost absent-mindedly against Venom’s, who spreads his legs wider to accommodate him between them. He’s too busy cataloguing the needy noises coming from those kiss-swollen lips – Kaz is usually the louder one, but today is full of surprises, it seems.

“Kaz...” Snake moans, hands tight on his thrusting hips. “Lube. Where’s the lube?” Kaz grins against his collar bone, nipping at the skin there with careful teeth until he leaves a mark; he takes pity on his partner quickly, though, his own patience stretched thin.

He has to search for the supplies for a moment, leaning away from Venom who busies himself with Kaz’s belt buckle and fly, slipping his flesh hand inside and under his briefs to palm his hard cock. _There!_ Kaz settles back onto his knees with a small tub of lube and a condom in hand and takes a moment to thrust into the dry warmth of Snake’s hand, hissing at the pressure that’s good but not enough.

“Impatient, are we?” Kaz pants, letting his own eagerness slide. He opens the lid and dips his left index and middle finger into the viscous substance, spreading and warming it one-handedly. He doesn’t know how the lube would affect his prosthetics, and he’s in no rush to find out.

Then, something occurs to him. Kaz’s eyes widen. “V, have you done this before?” His partner’s eye is fixed on the slicked fingers now resting idly on his abdomen, and it takes a moment for the question to register.

“I–“, he starts, but trails off, furrowing his brow. Kaz recognizes the distant expression: Venom's digging through his memories and coming up blank. “I don’t know. Can’t remember."

 _I should’ve thought this through first._ Kaz exhales slowly, willing himself to calm down and take it slow. “Okay. Still want it though?” He smiles at the eager nod, leaning down for a quick kiss. His next words are whispered against slightly parted lips. “Good. Spread your legs for me.”

Venom complies, parting his muscular thighs to bare his erection that twitches at Kaz’s heated stare. Kaz throws him a sly glance before he takes him in hand, stroking the entire length to get him to relax; he bends down to press a kiss against tensed abdominals, wandering down the V-shape of his pelvis. Breathing in Snake’s familiar scent, he notes that it's muskier than usual and groans at the thought that he didn’t even take the time to shower – he came directly to his quarters from whatever Ocelot wanted to show him...

Snake’s muscles bunch when he shifts, threading through Kaz’s hair with his bionic hand. “I need you, Kaz”, he says roughly and Kaz translates it to _hurry the hell up_. He smirks, liking the way his lover is desperate for it; he replaces his hand with his tongue gliding hot and wet over his stiff cock, sucking teasingly at the head. The resulting moan goes straight to his groin and he pushes his loosened pants down his hips to free his own erection, resisting the need to give himself a few tugs to ease the pressure building there.

Kaz places his wetted fingers against Venom’s entrance instead and begins to stretch him expertly, knowing how to reduce the uncomfortable sensation of being penetrated from his own experience. It doesn’t help that he’s so damn _tight_ , though, almost pushing out the digits buried inside him to the second knuckle.

“Relax, V”, he reminds him gently, pressing a kiss to Snake’s leaking cock. The other replies with a huffed “I’m trying”, sounding strained but otherwise fine. Kaz watches his face as he presses his fingers deeper, taking stock of the way he bites his lips to muffle his pained grunt, how he clenches his eye shut. It takes a few more minutes to get him to loosen up, but when he does the labored breaths turn to pleased pants, a drop of precum running down his length. Satisfied, Kaz pulls out of him and wraps his hand around the hard flesh, spreading the liquid with firm strokes. “V, you with me?”

Venom nods wordlessly, opening his eye. He takes in his partner with a hazy look before he lets his legs fall open wider. “Kaz... Please.” Kaz exhales steadily, nodding to himself as he shifts up higher on the bed, propping Snake’s legs around his hips. The need to just take him then and there is almost overwhelming, his cock painfully hard by now.

Kaz reaches for the condom, ripping the package open with his teeth and rolling it on before he applies a generous amount of slick. He can’t help the gasp at the slippery feeling of his own hand, stroking himself for a few seconds as he takes in the sight of his utterly debauched lover sprawled in front of him. “Ready?”

“ _Coño_ , Kaz – stop teasing and fuck me already”, Venom growls, tightening his legs around him and pulling him closer. Kaz chuckles darkly, leaning in to rest his full weight on him while he steadies his cock against his entrance. He reminds himself to go slow and caresses Venom’s thigh, feeling those powerful muscles tremble from the teasing touch – then he pushes into him, the ring of muscle parting easily for his solid length.

Kaz sheaths himself in one long thrust, breathing through it. “You’re so fucking tight, V. Christ...” The feeling of those clenching walls around him is incredible, more so because he can see his own pleasure reflected on Snake’s face, who has his flesh arm draped across his eyes and the bed sheets gripped tight with his prosthetic. Kaz rocks his hips into him, drawing out further and further until he’s thrusting into him steadily, skin slapping against skin, their bodies meeting again and again.

He doesn’t stop as he bends down, pressing his heaving chest against Venom’s and resting his weight on both his arms to either side of his head. Their gazes lock, both half-lidded and unfocused as Kaz plunges deeper into his lover, ending every thrust with a sensual roll that pushes him against all the right places, judging by the reaction. Snake’s cock twitches, leaking steadily between them and adding to the wet and sticky contact of their sweaty skin.

Wrapping his hand around his neck, Venom draws him into an open-mouthed kiss that neither bothers to execute properly, his mismatched hands stroking down Kaz’s back. His fingers dig into his lower back at a particularly hard thrust; Snake moans his name, breaking the kiss to pant against his jaw instead.

“Yeah, that’s right”, Kaz growls, repeating the move. He feels him tense around and under him, another drawn-out groan falling from Venom’s reddened lips. “You take me so well, V... How close are you?”

“Close”, his partner grunts out, arching into him-

Kaz stops.

“No, no, Kaz, por favor–“

He shushes him, pulling out smoothly before he hooks his bionic limb around Snake and flips him over; it’s so _easy_ , his prosthetic lifting his considerable weight like it’s nothing. _I should’ve gotten these way earlier_ , he thinks – before the sight of the naked expanse of his lover’s back and ass takes his ability to think straight at all. He draws Venom’s flesh arm around to his back, keeping the pressure light. “This alright?”, he asks, running his metal fingers carefully down his tensed side until he relaxes again.

Snake nods, pushing up into Kaz’s cock that rests against the cleft of his ass. His legs are spread in an obvious invitation, his face turned to the left to fix him with an intense gaze. The want in that blue eye hits Kaz like a physical punch to the gut and he groans, tightening his grip on his wrist before he takes him again, thrusting in with ease.

“Estuve pensando en ti todo el día”, he murmurs against Venom’s back, pulling him flush against his chest. “Spread out and panting around my cock. Cómo te sientes, V?”

“Full”, he answers, his voice tight. “Just– _ah_ , rico. Kaz, dame más. _Más duro–_ “ He whines low in his throat as Kaz obliges and picks up the pace, burying himself deep inside every time. Feeling his partner getting close again, he maintains the hold on his arm with his prosthetic and wraps his organic hand around his dripping cock, squeezing tightly.

"Ven por mí."

The effect ist instanteneous: Venom's passage clamps down around him, mouth opened in a near-silent moan as he comes all over the sheets and Kaz's fingers. Kaz rides him through it; he feels his own release creeping up on him, balls drawing up and cock pulsing in that tight heat. Still, he withdraws when Snake starts to tremble from overstimulation, removing the condom to jack himself off with his hand slicked by lube and come. His vision whites out from the intensity of his orgasm, hearing himself cry out Venom’s name as he shoots his load all over his scarred back.

Vision blurry and ears ringing, it takes a moment for his surroundings to get into focus again. “Fuck”, Kaz curses breathlessly, slumping against Snake in sudden exhaustion. The other merely huffs, looking boneless himself. Minutes tick by as their breathing slowly calms down, sweat cooling on their skin. Despite finishing last, Kaz is the first to move, checking up on his partner with a soft touch to his shoulder. “V?”

Said man hums tiredly in response but turns around with a wince, sprawling on his back shamelessly. Kaz presses a chaste kiss to his swollen lips, murmuring a quiet apology against the corner of his mouth – but Venom shakes his head, nuzzling his jaw. “Te amo”, he whispers hoarsely, drawing him close to his chest.

Kaz laughs, nipping at his shoulder. “Sap.” He feels Snake shrug – _So what?_ – and relaxes against him, humming contently. “C’mon, we gotta change the sheets. A shower would be nice, too.” The other merely grunts, settling in deeper into the stained sheets. “V–”

“We’ve survived worse, Kaz. ‘m tired.”

Kaz would press the point, but he feels his eyelids drooping. He yawns. “First thing in the morning, though...”

“Yeah, yeah.”

**Notes for the Chapter:**

> Sub!V/Top!Kaz - reblog if you agree...
> 
>    
> Spanish translations:
> 
> coño - damn, fuck [lit. cunt]
> 
> por favor - please
> 
> Estuve pensando en ti todo el día. - I've been thinking about you all day.
> 
> Cómo te sientes? - How do you feel?
> 
> rico - good [lit. delicious, as in food]
> 
> Dame más. - Give me more.
> 
> más duro - harder
> 
> Ven por mí. - Come for me.
> 
> Te amo. - I love you.


End file.
